To accommodate wind power as safely as possible and deal with the uncertainties of the output power of winddriven generators,a min-max-min two-stage robust optimization model is presented,considering the unit commitme...To accommodate wind power as safely as possible and deal with the uncertainties of the output power of winddriven generators,a min-max-min two-stage robust optimization model is presented,considering the unit commitment,source-network load collaboration,and control of the load demand response.After the constraint functions are linearized,the original problem is decomposed into the main problem and subproblem as a matrix using the strong dual method.The minimum-maximum of the original problem was continuously maximized using the iterative method,and the optimal solution was finally obtained.The constraint conditions expressed by the matrix may reduce the calculation time,and the upper and lower boundaries of the original problem may rapidly converge.The results of the example show that the injected nodes of the wind farms in the power grid should be selected appropriately;otherwise,it is easy to cause excessive accommodation of wind power at some nodes,leading to a surge in reserve costs and the load demand response is continuously optimized to reduce the inverse peak regulation characteristics of wind power.Thus,the most economical optimization scheme for the worst scenario of the output power of the generators is obtained,which proves the economy and reliability of the two-stage robust optimization method.展开更多
Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering ...Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering largescale wind-power transmission.First,the unique voltage characteristics of half-wavelength lines are deduced based on the distributed parameter model.In the secondary voltage-control level,reactive power-transmission limits of half-wavelength lines are introduced as another control objective except for tracing the pilot bus voltage reference.Considering the uncertainty and fluctuation of wind power,the overvoltage risk-assessment method of half-wavelength lines is presented to determine specific voltage-control strategies.Simulation results demonstrate that the proposed voltage-control method delivers superior tracking performance according to a voltage reference value and prevents the overvoltage risk of halfwavelength lines effectively in different wind-power penetrations.展开更多
Wind-power （WP） estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. E...Wind-power （WP） estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. Estimating the output power of a wind energy conversion unit （WEC） mainly bases on the incident wind speed at the unit site by using the power characteristic curve. In addition, several time-series models have been using in wind speed forecasting. These models are characterized with requiring a large set of data. In order to prevent from the wind speed measurement and the need of a precise wind turbine model, an novel method basing on neural network and the grey predictor model GM （1,1） is proposed. Though the method, the estimating model can be built only by using the experimental data, which are obtained from the WP system in laboratory. The effectiveness of the estimating model is confirmed by the simulation results.展开更多
This paper presents a scalar volt per hertz(V/f)control technique for maximum power tracking of a grid-connected wind-driven brushless doubly fed reluctance generator(BDFRG).The proposed generator has two stator windi...This paper presents a scalar volt per hertz(V/f)control technique for maximum power tracking of a grid-connected wind-driven brushless doubly fed reluctance generator(BDFRG).The proposed generator has two stator windings namely;power winding,directly connected to the grid and control winding,connected to the grid through a bi-directional converter.In order to enhance the performance of the proposed scalar-control strategy,a soft starting method is suggested to avoid the over-current of the bi-directional converter.Moreover,the capability of generator speed estimation for sensorless control is also studied.The capability of the proposed scalar-control technique is validated using a sample of simulation results.In addition,the presented simulation results ensure the effectiveness of the proposed control strategy for maximum wind-power extraction under windspeed variations.Furthermore,the results show that the estimated generator speed is in a good accordance with the actual generator speed which supports sensorless control capability.展开更多
大规模风电并网导致电力系统惯量和一次调频响应资源减少,大扰动下系统频率安全问题突出。为应对风电不确定性和系统惯量降低的挑战,提出计及风电频率支撑能力和运行风险的鲁棒机组组合(unitcommitment,UC)模型。首先,通过系统发生有功...大规模风电并网导致电力系统惯量和一次调频响应资源减少,大扰动下系统频率安全问题突出。为应对风电不确定性和系统惯量降低的挑战,提出计及风电频率支撑能力和运行风险的鲁棒机组组合(unitcommitment,UC)模型。首先,通过系统发生有功扰动后频率偏差动力学摆动方程建立频率安全的运行约束模型,并嵌入到UC问题中。其次,考虑到风电出力不确定性,提出风电出力鲁棒可行域定义以表征系统接纳风电的安全运行范围,并基于此提出系统运行风险模型。最后,基于两阶段鲁棒优化理论提出计及风电频率支撑能力和运行风险的UC鲁棒优化模型,并采用列和约束生成(column and constraint generation,C&CG)算法求解该模型。在IEEE9和IEEE118节点测试系统进行仿真分析,结果验证了所提模型的有效性。展开更多
基金supported by the Special Research Project on Power Planning of the Guangdong Power Grid Co.,Ltd.
文摘To accommodate wind power as safely as possible and deal with the uncertainties of the output power of winddriven generators,a min-max-min two-stage robust optimization model is presented,considering the unit commitment,source-network load collaboration,and control of the load demand response.After the constraint functions are linearized,the original problem is decomposed into the main problem and subproblem as a matrix using the strong dual method.The minimum-maximum of the original problem was continuously maximized using the iterative method,and the optimal solution was finally obtained.The constraint conditions expressed by the matrix may reduce the calculation time,and the upper and lower boundaries of the original problem may rapidly converge.The results of the example show that the injected nodes of the wind farms in the power grid should be selected appropriately;otherwise,it is easy to cause excessive accommodation of wind power at some nodes,leading to a surge in reserve costs and the load demand response is continuously optimized to reduce the inverse peak regulation characteristics of wind power.Thus,the most economical optimization scheme for the worst scenario of the output power of the generators is obtained,which proves the economy and reliability of the two-stage robust optimization method.
基金supported by State Grid Corporation of China,Projects under Grant 520626200031National Natural Science Foundation of China,No.51877200。
文摘Half-wavelength transmission can transmit large-scale renewable energy over very long distances.This paper proposes an improved steady-state voltage-control method for half-wavelength transmission systems considering largescale wind-power transmission.First,the unique voltage characteristics of half-wavelength lines are deduced based on the distributed parameter model.In the secondary voltage-control level,reactive power-transmission limits of half-wavelength lines are introduced as another control objective except for tracing the pilot bus voltage reference.Considering the uncertainty and fluctuation of wind power,the overvoltage risk-assessment method of half-wavelength lines is presented to determine specific voltage-control strategies.Simulation results demonstrate that the proposed voltage-control method delivers superior tracking performance according to a voltage reference value and prevents the overvoltage risk of halfwavelength lines effectively in different wind-power penetrations.
文摘Wind-power （WP） estimation is necessary for power system in several operations, which are as the optimal power flow between conventional units and wind farms, generators scheduling, and electricity market bidding. Estimating the output power of a wind energy conversion unit （WEC） mainly bases on the incident wind speed at the unit site by using the power characteristic curve. In addition, several time-series models have been using in wind speed forecasting. These models are characterized with requiring a large set of data. In order to prevent from the wind speed measurement and the need of a precise wind turbine model, an novel method basing on neural network and the grey predictor model GM （1,1） is proposed. Though the method, the estimating model can be built only by using the experimental data, which are obtained from the WP system in laboratory. The effectiveness of the estimating model is confirmed by the simulation results.
文摘This paper presents a scalar volt per hertz(V/f)control technique for maximum power tracking of a grid-connected wind-driven brushless doubly fed reluctance generator(BDFRG).The proposed generator has two stator windings namely;power winding,directly connected to the grid and control winding,connected to the grid through a bi-directional converter.In order to enhance the performance of the proposed scalar-control strategy,a soft starting method is suggested to avoid the over-current of the bi-directional converter.Moreover,the capability of generator speed estimation for sensorless control is also studied.The capability of the proposed scalar-control technique is validated using a sample of simulation results.In addition,the presented simulation results ensure the effectiveness of the proposed control strategy for maximum wind-power extraction under windspeed variations.Furthermore,the results show that the estimated generator speed is in a good accordance with the actual generator speed which supports sensorless control capability.
文摘大规模风电并网导致电力系统惯量和一次调频响应资源减少,大扰动下系统频率安全问题突出。为应对风电不确定性和系统惯量降低的挑战,提出计及风电频率支撑能力和运行风险的鲁棒机组组合(unitcommitment,UC)模型。首先,通过系统发生有功扰动后频率偏差动力学摆动方程建立频率安全的运行约束模型,并嵌入到UC问题中。其次,考虑到风电出力不确定性,提出风电出力鲁棒可行域定义以表征系统接纳风电的安全运行范围,并基于此提出系统运行风险模型。最后,基于两阶段鲁棒优化理论提出计及风电频率支撑能力和运行风险的UC鲁棒优化模型,并采用列和约束生成(column and constraint generation,C&CG)算法求解该模型。在IEEE9和IEEE118节点测试系统进行仿真分析,结果验证了所提模型的有效性。
